Radio communication device

1. A radio communication device comprising: a voice level comparator configured to compare a level of a voice signal collected by a microphone with a VOX level; a transmission determination unit configured to instruct a transmitter to transmit the voice signal, when the level of the voice signal is equal to or greater than the VOX level, based on a comparison result by the voice level comparator; a switch; a timer configured to start to measure an elapsed time from a point of time when the switch is operated; and a VOX level selector configured to set a first VOX level as the VOX level when the elapsed time measured by the timer exceeds a reference elapsed time, and to set a second VOX level which is smaller than the first VOX level as the VOX level when the elapsed time measured by the timer stays within the reference elapsed time.

2. A radio communication device comprising: a voice level comparator configured to compare a level of a voice signal collected by a microphone with a VOX level; a transmission determination unit configured to instruct a transmitter to transmit the voice signal, when the level of the voice signal is equal to or greater than the VOX level, based on a comparison result by the voice level comparator; a squelch processor configured to instruct a mute controller to mute a received signal generated by a receiver, when a noise level of the received signal is equal to or greater than a threshold value; a timer configured to start to measure an elapsed time from a point of time when the squelch processor instructs to mute the received signal; and a VOX level selector configured to set a first VOX level as the VOX level when the elapsed time measured by the timer exceeds a reference elapsed time, and to set a second VOX level which is smaller than the first VOX level as the VOX level when the elapsed time measured by the timer stays within the reference elapsed time.

3. The radio communication device according to claim 2 , further comprising a monitor switch to cause the mute controller to instruct the squelch processor to unmute the received signal, only for a period during which the monitor switch is pressed, wherein the timer measures an elapsed time from a point of time when the squelch processor instructs the mute controller to mute the received signal, by releasing a pressing of the monitor switch.

4. The radio communication device according to claim 3 , further comprising a delay controller configured to delay the voice signal collected by the microphone for a predetermined time, wherein the transmission determination unit instructs the transmitter to transmit a delayed voice signal by the delay controller, when the elapsed time measured by the timer stays within the reference elapsed time, and when the level of the voice signal collected by the microphone exceeds the second VOX level.

5. The radio communication device according to claim 4 , wherein the delay controller comprises: a buffer configured to delay and output the voice signal collected by the microphone by recording and reproducing the voice signal for a predetermined time; and a bypass unit configured to output the voice signal collected by the microphone without delaying the voice signal, and wherein the transmission determination unit instructs the transmitter to transmit the voice signal output from the buffer, when the elapsed time measured by the timer stays within the reference elapsed time, and to transmit the voice signal output from the bypass unit, when the elapsed time measured by the timer exceeds the reference elapsed time.

6. The radio communication device according to claim 5 , wherein the delay controller stops a function of the buffer when the elapsed time measured by the timer exceeds the reference elapsed time.